Tetragoneura ruuhijarvii Polevoi & Jakovlev, 2011, sp. n.

4. Tetragoneura ruuhijarvii sp. n.

(Fig. 2: E, F; 3: C, D)

Holotype: 3, FINLAND, Ta: Heinola, Taypale (alt. 100 m), 17.9.– 28.9.1990, (ZMH, Kaila & Ruskanen leg.). Paratypes: 1 3, FINLAND, Ta: Lammi, Evo, Lapinjärvi, 12.7.– 27.7.2004 (ZMH, J. Jakovlev leg.); 1 Ƥ, Ta: Lammi, Evo, Leipäsuonaho, 30.6.– 27.9.2005 (ZMH, J. Jakovlev leg.).

Other material examined. FINLAND: 2 3, Ta: Lammi, Evo, Lapinjärvi, 28.8.– 04.10.2004, (FRIP, J. Jakovlev leg.); 2 3, Ta: Lammi, Evo, Leipäsuonaho, 28.8– 04.10.2004 (METLA, J. Jakovlev leg.); 1 3, same place, 30.6.– 27.9.2005 (METLA, J. Jakovlev leg.); 1 3, Ab: Karjalohja, Karkali Strict Nature Reserve, 27.8.– 04.10.2004 (METLA, J. Jakovlev leg.).

Etymology. Named in a honour of professor Rauno Ruuhijärvi to acknowledge his great contribution to the nature protection in Finland and Russian Karelia.

Diagnostic characters. This species is related to Nearctic T.nitida Adams which has similar general type of male terminalia (see Chandler, 1980, Fig. 1, 2). Differs distinctly by the shape of submedian lobes of the gonocoxite and presence of curved seta at the base of the gonostylus.

Description. Male (n=3)

Head shining dark-brown to black, covered with short pale hairs and with several long proclinate setae on vertex. Lateral ocellus separated from eye margin by distance of 2.3 times its own diameter. Palpus yellow. Clypeus dark-brown, clothed with short hairs. Antenna uniformly brown. Fifth flagellomere about as long as wide. Scape and pedicel with long black setae apically. Eyes densely covered with minute hairs.

Thorax. Scutum shining dark-brown, clothed with evenly distributed pale hairs and with some longer black bristles. Scutellum and pleurae dark-brown, thinly grey dusted. Antepronotum and proepisternum haired and with bristles, the rest of the pleurae bare.

Wing length 2.78–2.91[mean value 2.87] mm. Wing hyaline, veins yellow, costa and radius brownish. C extending up to the middle of distance between R5 and M1. Sc short, ending free. R4 developed, forming elongated small cell (about 4–6 times longer than wide). R1 2.1–2.6 times as long as ta. Stem of M-fork about 1.6–1.7 times as long as ta. Base of CuA-fork lies under the base of ta. Macrotichia well developed on radial veins, distal half of ta, distal 2/3 of M1, whole M2, branches and stem of CuA-fork and A1. Haltere yellow.

Legs yellow. Front tibia with 0–1 pd and 2–4 small pv. Mid tibia with 3–5 ad 5–6 pd, 3–4 p and 6–7 pv. Hind tibia with 12–13 ad, 12–15 pd. Ratio of tibia to first tarsomere for front, mid and hind legs: 1.53–1.76 [1.66]; 1.59– 1.69 [1.64]; 1.97–2.18 [2.05]. Front tibia with one spur, mid tibia with two spurs (av spur about 1/2 as long as pv spur), hind tibia with two spurs (av spur is about 3/4 as long as pv spur). Sensory organ on t2 not developed.

Abdomen brown, covered with long pale hairs. Terminalia (Fig. 2: E, F) brown. Gonocoxites with submedian lobes widened apically and small complementary appendages laterally. Gonostylus attenuated to apex with curved spine at base. Tergite 9 divided into two separate sclerites, cerci rounded.

Female. (n=1). Wing length 2.73 mm. C extending well beyond the middle of distance between R5 and M1. R1 1.98 times as long as ta. Stem of M-fork about 1.86 times as long as ta. Ratio of tibia to first tarsomere for front, mid and hind legs: 1.34; 1.39; 2.09. Mid tibia with av spur about 2/3 as long as pv spur, hind tibia with av spur subequal to pv spur. In other respect similar to male. Terminalia as in Fig. 3: C, D. Gonocoxite 8 wide, rounded apically in lateral view, with more or less uniform setae. Tergite 10 with several long setae. Hypoproct with small setae laterally, basal one very long. First segment of cerci angled in lateral view. Second segment ovate in lateral and ventral view.

Biology. Holotype was collected with polypore trap (Kaila 1993) set on fruiting body of polypore fungus Fomes fomentarius in mixed forest. Other specimens were obtained with Malaise and emergence traps. The latter was placed on burnt fallen trunk of silver birch (Betula pendula) bearing fruiting bodies of Chondrostereum purpureum in basal part. The habitat was clear-cut treated with prescribed burning and with some retained trees.

Remarks. Association of the single female is based on co-occurrence in the emergence trap

Distribution. Eastern Fennoscandia. Known only from Finland.